Kone joined Sunderland from French club Lorient in the January transfer window, while attacking midfielder Khazri switched from Bordeaux.
“Myself and Wahbi have come in and offered something extra to the team, him in attack and me in defence, and with the other players and their quality in the team we have to go and do better,” Kone told Sunderland’s official website.
Sunderland’s performances and results have improved since January, although the Black Cats still remain in danger of getting relegated to the Championship at the end of the season.
Kone has created four chances in seven Premier League appearances for the Black Cats so far this campaign.
The 27-year-old Ivory Coast international centre-back has a pass accuracy of 66% and a shot accuracy of 40%, and has won 20 headers, two dribbles and four tackles.
Khazri has scored one goal and created 18 chances in seven league matches for Sunderland so far this season.
The 25-year-old Tunisia international attacking midfielder has a pass accuracy of 75% and a shot accuracy of 33%, and has won one header, 12 dribbles and 15 tackles.